diff --git a/docs/development.rst b/docs/development.rst
--- a/docs/development.rst
+++ b/docs/development.rst
@@ -62,6 +62,40 @@ 4. Install required packages in the virt
 
      workon conntrackt && pip install -r ~/projects/conntrackt/requirements/development.txt
 
+5. Download and unpack `Mozilla Firefox
+   <https://www.mozilla.org/en-US/firefox/>`_ version **57.0.x** for
+   your platform into directory ``test_binaries/``. If using 64-bit
+   GNU/Linux distribution, this should be as easy as:
+
+   .. warning::
+      In order to ensure the functional tests run well, it is
+      important to use correct combination of geckodriver and Mozilla
+      Firefox.
+
+   ::
+
+      workon conntrackt && \
+          cd test_binaries/ && \
+          wget 'https://ftp.mozilla.org/pub/firefox/releases/57.0.2/linux-x86_64/en-US/firefox-57.0.2.tar.bz2' && \
+          tar xjf firefox-57.0.2.tar.bz2
+
+6. Download `geckodriver
+   <https://github.com/mozilla/geckodriver/releases>`_ version
+   **v0.19.1**. If using 64-bit GNU/Linux distribution, this should be
+   as easy as:
+
+   .. warning::
+      In order to ensure the functional tests run well, it is
+      important to use correct combination of geckodriver and Mozilla
+      Firefox.
+
+   ::
+
+      workon conntrackt && \
+          cd test_binaries/ && \
+          wget 'https://github.com/mozilla/geckodriver/releases/download/v0.19.1/geckodriver-v0.19.1-linux64.tar.gz' && \
+          tar xzf geckodriver-v0.19.1-linux64.tar.gz
+
 
 Development/test Django project
 -------------------------------